Critical behavior in the inverse to forward energy transition in two-dimensional magnetohydrodynamic flow.
Critical behavior in the inverse to forward energy transition in two-dimensional magnetohydrodynamic flow.
复制标题
二维磁流体动力流中逆向能量转变和正向能量转变的关键行为。
作者：
K. Seshasayanan;A. Alexakis
本文研究了在二维磁流体力学流动中，当磁力与机械力的比值变化时，从能量的逆级联到能量的正级联的临界转变。研究发现，临界转变是两个相互竞争的过程的结果。第一个过程是由于水动力相互作用和级联的能量到大尺度。第二个过程将小尺度磁场耦合到大尺度流动，通过非局部机制将能量转移回小尺度。在边际，两个级联都存在，并相互抵消。绘制了相变的相空间图。
We investigate the critical transition from an inverse cascade of energy to a forward energy cascade in a two-dimensional magnetohydrodynamic flow as the ratio of magnetic to mechanical forcing amplitude is varied. It is found that the critical transition is the result of two competing processes. The first process is due to hydrodynamic interactions and cascades the energy to the large scales. The second process couples small-scale magnetic fields to large-scale flows, transferring the energy back to the small scales via a nonlocal mechanism. At marginality the two cascades are both present and cancel each other. The phase space diagram of the transition is sketched.